#elif用法
# age=30
# if age < 18:
#     print("you are underaged")
# elif age >=18 and age <30:
#     print("you are middle-aged")
# else:
#     print("you are old")
#
# #判断闰年
# year = int(input("请输入年份："))
# if(year %4 == 0 and year % 100 != 0)or(year%400 ==0):
#     print("%d是闰年"% year)
# else:
#     print("%d不是闰年"% year)

# #abc比较大小
# a = int(input("请输入a:"))
# b = int(input("请输入b:"))
# c = int(input("请输入c:"))
# if a>b:
#     if a>c:
#         print("a is the largest")
#     else:
#         print("c is the largest")
# else:
#     if b>c:
#         print("b is the largest")
#     else:
#         print("c is the largest")
from math import sqrt
#产生随机数
# from random import random, randint
# num = randint(1,100)
# while True:
#     guess = int(int(input("请输入一个数字：")))
#     if guess>num:
#         print("你猜大了")
#     elif guess<num:
#         print("你猜小了")
#     else:
#         print("猜对了")
#         break
# #逢7
# for i in range(1,100+1):
# #    if i % 7 ==0 or str(i).find('7') !=-1:
# #    if i % 7 ==0 or str(i).count('7') >0:
#     if i % 7 ==0 or '7' in str(i) !=-1:
#         print(i,end="\t")
